Process for the preparation of anthraquinone compounds



Patented Mar. 16, 1937 V 2,074,306

UNITED STATES PATENT OFFICE PROCESS FOR THE PREPARATION OF ANTHRAQUINONE COMPOUNDS Myron S. Whelen, Milwaukee, Wis, assignor to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application June 24, 1936, Serial No. 87,117

4 Claims. (Cl. 260-57) This invention relates to the preparation of stand for several hours after room temperature anthraquinone compounds, more particularly to has been reached. The precipitated material is a newand improved process for the isolation of filtered off and sucked as dry as possible. If 6-halogen-l-anthraquinonesulfonio acids in subdesired, very pure material may be obtained by 5 stantially pure form directly from their sulfonareslurrying this product in about 3000 parts of tion mass. warm water, followed by filtration at about 40 Due to the formation of isomeric alpha-mono- C. The material so obtained is practically pure sulfonic acids in the sulfonation of beta-halogen- 6-chloro-anthraquinone-l-sulfonic acid sodium anthraquinones, it has been impossible to obtain salt.

10 pure o-halogen-l-anthraquinonesulfonic acid by The use of a potassium salt in place of the so- 10 that route. Where the diluted sulionation mass dium salt in the above example, apparently beis salted with a potassium salt, not only the cause of the insolubility of the potassium salt of 6-chloro-1-anthraquinonesulfonic acid is prethe G-chloro-l-anthraquinonesulfonic acid in dicipitated but other impurities which cannot be lute acid as well as the insolubility of the potas- 5 separated therefrom by known methods. sium salt of the isomeric and disulfonic acid bodies 5 It is, therefore, an object of this invention to present in the sulfonation mass, gives a very improvide a process for the preparation of relaure G-chloro-l-anthraquinonesulfonic acid potively pure 6-halogen-l-anthraquinonesulfonic tassium n- Th purity f the products is dea d d ect y frolfn beta-halqgen-anthraquinonetermined by converting them to the 1,6-dichloro- It is a further obJect to provide a new a effecanthraquinone which has a definite melting point. 20 tive method for separating fi-halogen-l-anthra- The melting point of the 1 m m (ll-11110118 directly from the Sulfonation mass, one obtained from the procedure above outlined, stantially free from isomers and other contamprior t reslurrying i w t r, is 190-195 0., while mating impurities, by a Simple, economical and the melting point of the dichloro compound chcommercially practical procedure tained by the use of potassium salt varies from 25 I h v n w un h v ly p r -h 162-1'73 c. Reslurrying of the sodium salt in gen-LaHthIaQHiHOIIBSHIfOHiC acids may be water as described above gives a product which tained in the form of the sodium salt by direct h a melting point of 195-200 0., while reslurrysulfonation 0f betah o e and ing of the potassium salt gives a product having 0 by direct precipitation of the sodium salt from the melting pgint of 173 1'73 h melting point, diluted sulfonation mass. According to the presfound in t literature for pure 1,6-dichloroanent invention the sulfonation mass is diluted in thmquinone is 202 (1, water to an acid concentration of from 5 to 10% and an amount of sodium carbonate is added Example 2 somewhat in excess of that necessary to form 200 parts of 25% oleum, 35 parts of oleum 35 the sodium Sa o t 6-halogen-anthlaquinoneand 2 parts of mercuric sulfate are mixed together sulfonic acids theoretically present in the solution. d h t d d r agitation to 60 C. parts of The fo ow g examples are given to more fully beta-bromoanthraquinone are added and the mass il ustrat th invention- The parts u are by is heated at 130 c. until sulfonation is complete.

4 Wei ht- It is then drowned in water and treated in a man- 40 Emmfllel ner analogous to that described in Example 1.

575 parts of 25% oleum, 100 parts of 65% oleum The product obtained is supstanfoiaiuy .pure and 3 parts of mercuric Sulfate are mixed together bromo-l-anthraquinonesulfonic acid sodium salt.

.. To effect the desired separation of the G-haloand heated to 60 C. To this solution are added h ulfo c d th 43 while stirring, 300 parts of beta-chloroanthragen 1 ant raqumone S me a 1 e sulfonation mass is preferably diluted to an acid concenqumone. The temperature is then slowly raised nation of approximately 5%, figured'on the and mamtamed at ntll amount of free sulfuric acid remaining in the sulfonation of the beta-chloroanthraquinone solution a1though t, 111 be obvious that the 50 complete The mass is then drowned in about exact concentration is not critical and may be 50 .9000 pa t of wa water containing 5 pa f raised or lowered to some extent. Too great a sodium chlorate. It is then heated to 90-100 C. dilution decreases the yield of the desired product for one-half hour and filtered, if any solid mateto some degree due to the slight solubility of the rial is present. To the filtrate parts of soda sodium salt, while higher acid concentrations are 55 ash are added and the suspension is allowed to less desirable due to mechanical difficulties ex- 55 perienced in filtering, etc. Acid concentrations of from 4 to 10% have given satisfactory results.

The exact amount of sodium carbonate or other sodium salt to be added to the solution may be varied within reasonable limits. Sufiicient should be added to form the sodium salt of all of the 6-chloroanthraquinonesulfonic acid present with some excess which operates to salt out the desired sulfonic acid. The final concentration of the salt solution figured as sodium sulfate may vary be tween from about 0.5 to 2% without unduly altering the purity or yield of the desired product. In using sodium chloride or sulfate equivalent amounts to that given for the sodium carbonate should be used.

I claim:

1. In the process for preparing 6-halogen1- anthraquinonesulfonic acid by the direct sulfonation of beta-halogen-anthraquinone, the steps which comprise diluting the sulfonation mass in Water and precipitating the 6-halogen-1-anthraquinonesulfonic acid as the sodium salt.

2. In the process for isolating 6-chloro-1-anthraquinonesulfonic acid from the sulfonation mass in which it is formed by direct sulfonation of beta-chloroanthraquinone, the steps which comprise diluting the sulfonation mass to a sulfuric acid concentration of from 4 to- 10% and adding a sodium salt in suificient quantity to form the sodium salt of all of the 6-chl'oroanthra quinonesulfonic acid present.

3. In the process for isolating 6-chloro-1-anthraquinonesulfonic acid from the sulfonation mass in which it is formed by direct sulfonation of betachloroanthraquinone, the steps which comprise diluting the sulfonation mass to a sulfuric acid concentration of from 4 to 10% and adding a sodium salt in sufficient quantity to form the sodium salt of all of the fi-chloroanthraquinonesulfonic acid present, adding sufiicient excess te insure complete precipitation of all of the 6-chloro-l-anthraquinonesulfonic acid sodium salt, and filtering the product.

4. In the process for isolating 6-chloro-1-anthraquinone sulfonic acid from the sulfonation mass in which it is formed by direct sulfonation of beta-chloroanthraquinone, the steps which comprise diluting the sulfonation mass to a sulfuric acid concentration of from 4 to 10% and adding a sodium salt in suificient quantity to form the sodium salt of all of the 6-chloroanthraquinonesulfonic acid present, adding sufiicient excess to insure complete precipitation of all of the fi-chloro-l-anthraquinonesulfonic acid sodium salt, filtering the. product, reslurrying the filter cake in water and filtering to eflect a further purification.

MYRON S. WImLEN. 

